Rungo is a miner who had
discovered a hidden uranium deposit belonging to the Secret Society prior
to the first game. When the Secret Society learned of this, they kidnapped
his wife and child. After being led to the first Toshinden tournament,
he entered it to rescue them and was successful in his mission. One year
later, Rungo received a call for help from Gaia.
Gaia had hosted the tournament illegally and was now being branded a traitor
and marked for death by Uranus, one of his co-workers in the Secret Society.
Although Rungo had fought against him in the last tournament while trying
to save his family, he realized Gaia was not the one responsible for their
kidnap. Rungo agreed to help Gaia get revenge and entered the second tournament.
He was successful in destroying the Secret Society with the rest of the
fighters and eventually Uranus was killed. When a third tournament was
announced, Rungo learned that it was being hosted by the Organization and
that he was one of their targets. He entered the tournament to help destroy
the Organization.

As if the first Toshinden
didn't "borrow" its character design inspiration from Street Fighter
enough with Kayin and Eiji.... lol. To state the obvious, Rungo is clearly a beefed up Guile...
with a club. They altered Rungo's design in the later games (for obvious
reasons),
but he's really a bland design at the end of the day. Thankfully, the Toshinden
series has better designs than Rungo to offer.